Electrowetting display devices are known. In an off state of a picture element of such a device an oil covers a display area. In an on state the oil is retracted so as to cover less of the display area. To switch the picture element to the on state a voltage is applied via an electrically conductive fluid immiscible with the oil. To switch the picture element to the off state, the voltage is switched off. In examples where the oil is coloured, a radiation beam passing through the picture element when in the off state passes through the oil and is imparted with colour. However, when the picture element is in the on state, the beam does not pass through the oil meaning its colour remains substantially unchanged.
It is desirable to provide an improved electrowetting element.